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用于网络控制系统仿真

----------------------------------------------
 TrueTime 1.5
 Example: Wireless Ad-hoc Routing Using AODV
 Directory: $DIR/examples/AODV
----------------------------------------------

1. INTRODUCTION

This example describes a TrueTime implementation of the Ad-hoc 
On-Demand Distance Vector (AODV) routing protocol. See the TrueTime 
reference manual for a more comprehensive description of the example
and for references to AODV documentation.


2. COMPILING THE SIMULATION FILES

2.1 Configuring the TrueTime Environment

    Before starting Matlab, you must set the environment variable
    TTKERNEL to point to the directory with the TrueTime kernel files:

        Unix/Linux: > export TTKERNEL=$DIR/kernel
        Windows:  Control Panel / System / Advanced / Environment Variables

    Then add the following lines to your MATLAB startup script. This
    will set up all necessary paths to the TrueTime kernel files.

        addpath(getenv('TTKERNEL'))
        init_truetime;

2.2 Compilation

    As described in the reference manual it is possible to write a
    TrueTime simulation (i.e. the code functions for the tasks and the
    initialization commands) either as m-files or as C++ functions. For
    this example only the m-file approach is provided.

    Since the TrueTime archive contains pre-compiled files, no 
    compilation is required to run TrueTime in the Matlab version. 
    However, if needed, the files may be re-compiled by issuing the 
    command make_truetime from the command prompt.


3. SIMULATIONS

Open the model AODV.mdl to run the simulation. 

- The simulation example consists of seven nodes. Choose the option
  Update Diagram in the Edit menu to bring up an animation window of
  the simulation. This will show the original positions of the seven
  nodes and their respective signal reach.

- Run a simulation. In the simulation scenario, the left-most node
  (node 1) sends data periodically to node 7 with period 0.5.
  The initial route that is established is 1 -> 3 -> 5 -> 7. At time 
  t=3, node 5 starts to move which eventually leads to the route breaking. 
  At time t=10, node 6 repairs the route by moving in between node 4
  and 7. The printouts in the Matlab command window describe the actions 
  in the AODV layer in more detail. Also study the global variable
  routing_table. 

- Open and examine the file initsim.m. This file initializes the global 
  variables used in the simulation, e.g., the routing table and the node 
  positions. By changing the variable verbose from 0 to 1 even more 
  detailed AODV information will be displayed when the simulation is run.

- The global variables sent and received show the data that is sent
  (by node 1) and received (by node 7) in the simulation. Examine the 
  lengths of these vectors to determine how many messages that where lost 
  due to the delay in detecting and propagating the information about the 
  broken link back to the source node. (Answer: The messages sent at times 
  8.0002, 8.5002, and 9.0002 are lost.)

- The hello interval determines how fast the network will respond
  to broken links (and also the bandwidth overhead). Try changing the
  AODV parameter HELLO_INTERVAL (both in initsim.m and node_init.m) to 
  decrease the number of lost data messages. In this case only two messages 
  are lost.